It's the documentary that audiences and film critics are eating up.

In a covert six-month mission to expose the inside world of school lunches, 11-year-old Zachary Maxwell made "Yuck: A 4th Grader's Documentary About School Lunch" when he was a fourth-grader at a New York City public school.

Armed with hidden cameras, the precocious filmmaker went undercover to document dozens of lunches he was served at school.

During Zachary's investigation, he compared descriptions of lunch items on the school-provided menu with secretly recorded video of what he was actually being served.

"It sounded like it was coming from the finest restaurant, but what we were actually getting served, it wasn't too good," Zachary told ABC News.

His 19-minute movie has already been featured at film festivals this year, and will be shown in the Manhattan Film Festival June 21, something the now fifth-grader is quite proud of.

"I think it's a lot cooler than just watching it on a little TV screen," Zachary said on "Good Morning America" this morning in response to how it feels having his documentary become so successful. "And also watching with an audience on a big screen is really cool. Because when they laugh when they're supposed to laugh, it's the best feeling ever."

The New York City Department of Education visited Zachary's school after his film began circulating and says officials, "Provide students with healthy and delicious school meals that are low in fat, sodium and calories and we currently have more than 1,000 salad bars in our schools to provide more healthful options to students."

Zachary's father, CJ Maxwell, who helped the budding filmmaker put this documentary together, says he couldn't be prouder of his son, a student at Public School 130 in the Little Italy section of Manhattan.

"I think that he showed a lot of little spunk and spirit and we encouraged him to keep at it," Maxwell said.

Zachary admits while he was working on his undercover documentary, he was worried he'd get in trouble.

"Every day I was nervous I'd get in trouble, or worse, get suspended," he said.

But that hasn't stopped Zachary from continuing his behind-the-camera efforts. He's now working on a personal project about his fifth-grade class, he says, "Because we're all going to middle school our separate ways, so we have the memory of each other."

After he gets to middle school, Zachary said, he also has future plans for a documentary about "adolescence, puberty, and what middle school girls think about guys with braces."

"When I grow up," he said, laughing, "I want to be a big-shot filmmaker."